Friendship is a game mechanic in Pikmin Bloom, where every Pikmin has its own friendship level. Friendship is shown in the form of hearts. The lowest possible friendship is 0 filled hearts, and the maximum is 4 filled hearts. Getting a Pikmin to maximum friendship is a way to get Decor Pikmin.
Each heart of friendship requires 53 points of friendship to fill, so reaching 4 hearts requires a total of 212 friendship points. (To note is that the first, second, and last points of friendship gain within one heart do not visibly change its appearance, while the rest do.) The friendship points gained from various actions are as follows:
Pikmin visibly gain friendship after being fed nectar, after their expedition reward has been collected, and after the score of a mushroom challenge is displayed; this is shown by a heart briefly appearing above the Pikmin's head. If the friendship gain is enough to fill the current heart, the heart will persist for longer and expand with a special sound effect.
The most efficient way to raise a Pikmin's friendship is to feed it 5 nectar in a row (making sure the first is not white nectar if the Pikmin starts with a leaf). This is because the fifth feeding gives a major boost to friendship, enough to fill a fifth of a heart. A Pikmin will visibly hesitate before taking the nectar on the fifth feeding, which is how you can tell you're up to it. This strategy uses a lot of nectar for a large squad, so it can only be done occasionally; it is recommended to do it when nectar numbers are higher and petal numbers are lower, and to save fruit expeditions until after doing it.
Effects of friendship
When a Pikmin that didn't come from a huge seedling reaches the maximum friendship level of 4 hearts, a new expedition for a gift box will appear. The Pikmin that reached 4 hearts can be sent on this expedition, and upon getting back to the player, will turn into a Decor Pikmin.
Pikmin with a higher friendship level are stronger in mushroom challenges. The number of completed hearts a Pikmin has is used in the formula to calculate its attack power.
The following changes have been made to friendship over time: